Thermocouple device

ABSTRACT

A semiconductor device and method of making same are disclosed. In some embodiments, a method includes: forming a first thermoelectric conduction leg on a substrate; forming a second thermoelectric conduction leg on the substrate to be aligned with the first thermoelectric conduction leg along a same row; forming at least one intermediate thermoelectric conduction structure on an end of the second thermoelectric conduction leg; forming a contact structure to couple the first and second thermoelectric conduction legs via the at least one intermediate thermoelectric conduction structure; and recessing the substrate to form at least one trench substantially adjacent to a respective side edge of either the first thermoelectric conduction leg or the second thermoelectric conduction leg.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 15/637,900 filed Jun. 29, 2017, which is incorporated byreference herein in its entirety.

BACKGROUND

Thermoelectric power generation is a technique for converting thermalenergy into electric energy with the use of the “Seeback effect.” TheSeeback effect is a phenomenon in which a temperature difference givento opposing ends of a substance causes a thermal electromotive force inproportion to the temperature difference, whereby electric power (e.g.,a current or a voltage signal) can be taken out by externally coupling aload to the substrate. Devices operating based on such a technique(thermoelectric power generation) have been seen in various applicationssuch as, for example, wearable electronics, wireless sensor networks,system on chip circuits, etc.

In some cases, a thermocouple device, made of either conductor orsemiconductor material, can be placed across a temperature difference togenerate electric power based on the above-described technique.Generally, when the temperature difference is provided across respectiveends of the thermocouple device, which are typically referred to as hotand cold ends, respectively, a voltage (or current) signal (i.e., theelectric power) can be measured therebetween. Such a thermocouple deviceis typically categorized as one of various thermoelectric energygeneration (TEG) devices. In accordance with increasing needs for ahigh-performance and CMOS-compatible thermocouple device (e.g., aminiature size, low heat leakage, a reliable durability, etc.), various,material- and/or structure-wise, types of thermocouple devices have beenproposed to further improve performance of existing thermocoupledevices. However, such known thermocouple devices have not been entirelysatisfactory in order to provide desired performance while being able tobe fabricated using CMOS-compatible technologies.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that various features are not necessarily drawn to scale. In fact,the dimensions and geometries of the various features may be arbitrarilyincreased or reduced for clarity of discussion.

FIG. 1 illustrates a flow chart of an embodiment of a method to form athermocouple device, in accordance with some embodiments.

FIGS. 2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H, and 2J illustrate perspectiveviews of an exemplary thermocouple device, made by the method of FIG. 1,during various fabrication stages, in accordance with some embodiments.

FIGS. 2I and 2K illustrate corresponding top views of FIGS. 2H and 2J,respectively, in accordance with some embodiments.

FIG. 2L illustrates a corresponding cross-sectional view of FIG. 2J, inaccordance with some embodiments.

FIG. 3 illustrates a cross-sectional view of a sub thermocouple deviceof the thermocouple device, made by the method of FIG. 1, in accordancewith some embodiments.

FIG. 4A illustrates a corresponding cross-sectional view of FIG. 2J whena first sub etching process is performed, in accordance with someembodiments.

FIG. 4B illustrates a corresponding cross-sectional view of FIG. 2J whena second sub etching process is performed, in accordance with someembodiments.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following disclosure describes various exemplary embodiments forimplementing different features of the subject matter. Specific examplesof components and arrangements are described below to simplify thepresent disclosure. These are, of course, merely examples and are notintended to be limiting. For example, the formation of a first featureover or on a second feature in the description that follows may includeembodiments in which the first and second features are formed in directcontact, and may also include embodiments in which additional featuresmay be formed between the first and second features, such that the firstand second features may not be in direct contact. In addition, thepresent disclosure may repeat reference numerals and/or letters in thevarious examples. This repetition is for the purpose of simplicity andclarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

The present disclosure provides various embodiments of a novelthermocouple device and method of forming the same. In some embodiments,the thermocouple device includes a plurality of pairs of thermoelectricconduction legs, wherein the thermoelectric conduction legs of each pairare formed of respective semiconductor materials and with respectivedifferent dopant types. The thermoelectric conduction legs of each pairare coupled to each other at respective ends so as to form a pluralityof sub thermocouple devices that are each formed by two respectivethermoelectric conduction legs coupled to each other in series, and eachwith a respective dopant type. In some embodiments, the plural subthermocouple devices (i.e., the plural pairs of thermoelectricconduction legs) are disposed in parallel on a substrate with respectivethermoelectric conduction legs being alternatively arranged in terms ofthe dopant type. Further, the plural sub thermocouple devices may bephysically coupled to one another through one or more conductorstructures. As such, the plurality of sub thermocouple devices may be“electrically” coupled in series when a current/voltage signal isgenerated from each sub thermocouple device. In some embodiments, atrench may be formed on a top surface of the substrate and between twoadjacent thermoelectric conduction legs that each belongs to arespective sub thermocouple device. Such a trench may further improve aninsulation characteristic of the disclosed thermocouple device, whichadvantageously decreases respective heat leakage.

FIG. 1 illustrates a flowchart of a method 100 to form a thermocoupledevice according to one or more embodiments of the present disclosure.It is noted that the method 100 is merely an example, and is notintended to limit the present disclosure. As employed by the presentdisclosure, the thermocouple device refers to any device that canproduce electric power by using a temperature difference acrossrespective ends of the device. It is noted that the method of FIG. 1does not produce a completed thermocouple device. Accordingly, it isunderstood that additional operations may be provided before, during,and after the method 100 of FIG. 1, and that some other operations mayonly be briefly described herein.

In some embodiments, the method 100 starts with operation 102 in which asubstrate is provided. The method 100 continues to operation 104 inwhich a first plurality of thermoelectric conduction legs are formed onthe substrate. In some embodiments, the first plurality ofthermoelectric conduction legs are each formed of an n-type polysiliconmaterial. In some embodiments, the first plurality of thermoelectricconduction legs are aligned along a respective row. And two of the firstplurality of thermoelectric conduction legs that are respectivelydisposed along two closest rows are spatially staggered from oneanother, hereinafter “two closest ones” of the first plurality ofthermoelectric conduction legs. As such, a space can be spared on thesubstrate between one and a respective next closest one of the firstplurality of thermoelectric conduction legs.

The method 100 continues to operation 106 in which a second plurality ofthermoelectric conduction legs are formed on the substrate. In someembodiments, the second plurality of thermoelectric conduction legs areeach formed of a p-type silicon-germanium (SiGe) material. In someembodiments, the second plurality of thermoelectric conduction legs arealigned along a respective row. And two of the second plurality ofthermoelectric conduction legs that are respectively disposed along twoclosest rows are spatially staggered from one another, hereinafter “twoclosest ones of the second plurality of thermoelectric conduction legs.”As such, part of the second plurality of thermoelectric conduction legsmay be each disposed in the space on the substrate that is spared by thefirst plurality of thermoelectric conduction legs (i.e., a respectiveone and its next closest one), as mentioned above.

The method 100 continues to operation 108 in which two intermediatethermoelectric conduction structures are formed on respective ends ofeach of the second plurality of thermoelectric conduction legs. In someembodiments, the intermediate thermoelectric conduction structures areeach formed of an n-type polysilicon material.

The method 100 continues to operation 110 in which a plurality ofcontact structures are formed so as to couple the first and secondpluralities of thermoelectric conduction legs by the respectiveintermediate thermoelectric conduction structures. In some embodiments,a first portion of the contact structures are each coupled betweenrespective ones of the first and second pluralities of thermoelectricconduction legs that are disposed end-to-end along a respective row. Anda second portion of the contact structures are each coupled betweenrespective ones of the first and second pluralities of thermoelectricconduction legs that are disposed side-by-side along a respectivecolumn. As such, along each row, a sub thermocouple device can beprovided. More specifically, according to some embodiments, such a subthermocouple device is formed by the respective ones of the first andsecond pluralities of thermoelectric conduction legs that are coupled toeach other end-to-end by a respective one of the first portion of thecontact structures. Further, the sub thermocouple device formed alongthe respective rows can be coupled to each other side-by-side by arespective one of the second portion of the contact structures.

The method 100 continues to operation 112 in which a dielectric layer isformed on the substrate. In some embodiments, the dielectric layeroverlays the first and second pluralities of thermoelectric conductionlegs, the intermediate thermoelectric conduction structures, and thecontact features. The method 100 continues to operation 114 in which apatterned mask layer is formed over the dielectric layer. In someembodiments, the patterned mask layer includes a plurality of patterns(e.g., openings) that are each aligned with a space between tworespective adjacent sub thermocouple devices. The method 100 continuesto operation 116 in which a plurality of trenches are formed on a topsurface of the substrate. In some embodiments, the plurality of trenchesare formed using the patterned mask layer as a mask to etch respectiveportions of the dielectric layer and the substrate. Accordingly, theplurality of trenches may be each disposed in one of the above-mentionedspaces (i.e., the space between two respective adjacent sub thermocoupledevices).

In some embodiments, operations of the method 100 may be associated withperspective views of a thermocouple device 200 at various fabricationstages as shown in FIGS. 2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H, and 2J,respectively. For purposes of clarity of illustration, FIG. 2I shows atop view of the thermocouple device 200 corresponding to FIG. 2H; andFIGS. 2K and 2L show a top view and a cross-sectional view of thethermocouple device 200 corresponding to FIG. 2J, respectively. FIGS. 2Athrough 2L are simplified for a better understanding of the concepts ofthe present disclosure. For example, although the figures illustrate thethermocouple device 200, it is understood the thermocouple device 200may comprise any number of other device features (e.g., source and drainfeatures, a gate dielectric of a MOSFET (metal-oxide-semiconductorfield-effect-transistor), an isolation feature such as STI (shallowtrench isolation), FOX (filed oxide), and/or deep trenches, a buriedsemiconductor layer, a collector feature of a BJT (bipolar junctiontransistor), etc.), which are not shown in FIGS. 2A through 2L, forpurposes of clarity of illustration.

Corresponding to operation 102 of FIG. 1, FIG. 2A is a perspective viewof the thermocouple device 200 including a substrate 202 at one of thevarious stages of fabrication, according to some embodiments. In someembodiments, the substrate 202 comprises a crystalline silicon substrate(e.g., wafer). Further, in some embodiments, the crystalline siliconsubstrate 202 may be p-type doped, for example, including dopants ofgallium, boron, and/or aluminum. In some alternative embodiments, thesubstrate 202 may be made of some other suitable elementalsemiconductor, such as diamond or germanium; a suitable compoundsemiconductor, such as gallium arsenide, silicon carbide, indiumarsenide, or indium phosphide; or a suitable alloy semiconductor, suchas silicon germanium carbide, gallium arsenic phosphide, or galliumindium phosphide. Further, the substrate 202 may include an epitaxiallayer (epi-layer), may be strained for performance enhancement, and/ormay include a silicon-on-insulator (SOI) structure.

As mentioned above, the thermocouple device 200 may comprise any numberof other device features, according to some embodiments. Moreover, insome embodiments, the method 100 of FIG. 1 may be CMOS-compatible. Inother words, the operations of the method 100 can be reproduced by CMOStechnologies such as, for example, bipolarjunction-transistor-complementary-metal-oxide-semiconductor (BiCMOS)technologies. As such, in operation 102, when the substrate 202 isprovided, the substrate 202 may include at least one of the followingsdevice features: source and drain features, a gate dielectric of arespective MOSFET, an isolation feature such as STI, FOX, and/or deeptrenches, a buried semiconductor layer, a collector feature of arespective BJT, etc.

Corresponding to operation 104 of FIG. 1, FIG. 2B is a perspective viewof the thermocouple device 200 including a first plurality ofthermoelectric conduction legs 204, which are formed at one of thevarious stages of fabrication, according to some embodiments. Asmentioned above, the first plurality of thermoelectric conduction legs204 are each aligned along a respective row (e.g., the X direction), andany two closest ones of the first plurality of thermoelectric conductionlegs 204 are spatially staggered from one another so as to spare a spaceon the substrate 202 between one and a next closest one of firstplurality of thermoelectric conduction legs 204.

For example, as shown in the illustrated embodiment of FIG. 2B, thefirst plurality of thermoelectric conduction legs 204 include: 204-1,204-2, 204-3, 204-4, 204-5, 204-6, and 204-7. Each of the thermoelectricconduction legs 204-1, 204-2, 204-3, 204-4, 204-5, 204-6, and 204-7 isdisposed along a respective row. Moreover, the thermoelectric conductionleg 204-1 and the thermoelectric conduction leg 204-2 are spatiallystaggered from each other so as to spare a space 205-1 between thethermoelectric conduction legs 204-1 and its next closest one 204-3; thethermoelectric conduction leg 204-2 and the thermoelectric conductionlegs 204-3 spatially staggered from each other so as to spare a space205-2 between the thermoelectric conduction legs 204-2 and its nextclosest one 204-4; the thermoelectric conduction leg 204-3 and thethermoelectric conduction leg 204-4 are spatially staggered from eachother so as to spare a space 205-3 between the thermoelectric conductionlegs 204-3 and its next closest one 204-5; the thermoelectric conductionleg 204-4 and the thermoelectric conduction leg 204-5 are spatiallystaggered from each other so as to spare a space 205-4 between thethermoelectric conduction legs 204-4 and its next closest one 204-6; thethermoelectric conduction leg 204-5 and the thermoelectric conductionleg 204-6 are spatially staggered from each other so as to spare a space205-5 between the thermoelectric conduction legs 204-5 and its nextclosest one 204-7.

It is noted that, after the formation of the first plurality ofthermoelectric conduction legs 204 (e.g., 204-1 to 204-7), spaces 205-6and 205-7 can also be defined. In some embodiments, the space 205-6 maybe formed next to the thermoelectric conduction leg 204-1 (i.e.,end-to-end and along a same row), and between a first edge 202-1 of thesubstrate 202 and the thermoelectric conduction leg 204-2; and the space205-7 may be disposed next to the thermoelectric conduction leg 204-7(i.e., end-to-end and along a same row), and between a second edge 202-2of the substrate 202 and the thermoelectric conduction leg 204-6. Insome embodiments, the spaces 205-1 to 205-7 may be used to dispose asecond plurality of thermoelectric conduction legs therein, which willbe discussed in further detail below.

In some embodiments, each of the first plurality of thermoelectricconduction legs 204 is formed of a polysilicon material. Moreover, insome embodiments, each of the first plurality of thermoelectricconduction legs 204 is formed of an n-type polysilicon material, forexample, a polysilicon material doped with phosphorus, arsenic,antimony, or the like.

As mentioned above, each of the operations of the method 100 (FIG. 1) isBiCMOS compatible, in accordance with some embodiments. As such, in someembodiments, each of the first plurality of thermoelectric conductionlegs 204, formed in the operation 104 of FIG. 1, may include a gatefeature of a respective MOSFET. In some embodiments, such a “gate”thermoelectric conduction leg 204 may be formed using a suitablegate-forming process in BiCMOS technologies such as, for example, atomiclayer deposition (ALD), chemical vapor deposition (CVD), physical vapordeposition (PVD), plating, or a combination thereof.

Corresponding to operation 106 of FIG. 1, FIG. 2C is a perspective viewof the thermocouple device 200 including a second plurality ofthermoelectric conduction legs 208, which are formed at one of thevarious stages of fabrication, according to some embodiments. Asmentioned above, the second plurality of thermoelectric conduction legs208 are each aligned a respective row (e.g., the X direction), and oneof the second plurality of thermoelectric conduction legs 208 isspatially staggered from its respective two closest ones so that each ofthe thermoelectric conduction legs 208 can be disposed in a respectiveone of the spaces 205-1 to 205-7 (FIG. 2B).

For example, as shown in the illustrated embodiment of FIG. 2C, thesecond plurality of thermoelectric conduction legs 208 include: 208-1,208-2, 208-3, 208-4, 208-5, 208-6, and 208-7. Each of the thermoelectricconduction legs 208-1, 208-2, 208-3, 208-4, 208-5, 208-6, and 208-7 isdisposed along a respective row. Moreover, the thermoelectric conductionleg 208-1 is spatially staggered from the thermoelectric conduction legs208-2 and 208-6, which are closest to leg 208-1, so that thethermoelectric conduction leg 208-1 can be disposed in the space 205-1that is between the thermoelectric conduction legs 204-1 and 204-3 (FIG.2B). Similarly, the thermoelectric conduction leg 208-2 is spatiallystaggered from the thermoelectric conduction legs 208-1 and 208-3 sothat the thermoelectric conduction leg 208-2 can be disposed in thespace 205-2 that is between the thermoelectric conduction legs 204-2 and204-4 (FIG. 2B); the thermoelectric conduction leg 208-3 is spatiallystaggered from the thermoelectric conduction legs 208-2 and 208-4 sothat the thermoelectric conduction leg 208-3 can be disposed in thespace 205-3 that is between the thermoelectric conduction legs 204-3 and204-5 (FIG. 2B); the thermoelectric conduction leg 208-4 is spatiallystaggered from the thermoelectric conduction legs 208-3 and 208-5 sothat the thermoelectric conduction leg 208-4 can be disposed in thespace 205-4 that is between the thermoelectric conduction legs 204-4 and204-6 (FIG. 2B); the thermoelectric conduction leg 208-5 is spatiallystaggered from the thermoelectric conduction legs 208-4 and 208-7 sothat the thermoelectric conduction leg 208-5 can be disposed in thespace 205-5 that is between the thermoelectric conduction legs 204-5 and204-7 (FIG. 2B).

It is noted that, in some embodiments, the thermoelectric conduction leg208-6 is spatially staggered from the thermoelectric conduction leg208-1 so that the thermoelectric conduction leg 208-6 can be disposed inthe space 205-6 that is between the edge 202-1 and the thermoelectricconduction leg 204-2; and the thermoelectric conduction leg 208-7 isspatially staggered from the thermoelectric conduction leg 208-5 so thatthe thermoelectric conduction leg 208-7 can be disposed in the space205-7 that is between the edge 202-2 and the thermoelectric conductionleg 204-6.

In some embodiments, each of the second plurality of thermoelectricconduction legs 208 is formed of a silicon-germanium material. Moreover,in some embodiments, each of the second plurality of thermoelectricconduction legs 208 is formed of a p-type silicon-germanium material,for example, a silicon-germanium material doped with boron, gallium,aluminum, or the like.

Similarly, as mentioned above, each of the operations of the method 100(FIG. 1) is BiCMOS compatible, in accordance with some embodiments. Assuch, in some embodiments, each of the second plurality ofthermoelectric conduction legs 208, formed in the operation 106 of FIG.1, may include a base feature of a respective BJT. In some embodiments,such a “base” thermoelectric conduction leg 208 may be formed using asuitable base-forming process BiCMOS technologies such as, for example,ALD, CVD, PVD, plating, or a combination thereof.

Corresponding to operation 108 of FIG. 1, FIG. 2D is a perspective viewof the thermocouple device 200 including a plurality of intermediatethermoelectric conduction structures 210, which are formed at one of thevarious stages of fabrication, according to some embodiments. Morespecifically, each of the intermediate thermoelectric conductionstructures 210 (e.g., 210-1A, 210-1B, 210-2A, 210-2B, 210-3A, 210-3B,210-4A, 210-4B, 210-5A, 210-5B, 210-6A, 210-6B, 210-7A, and 210-7B) isdisposed at a respective end of a corresponding one of the secondplurality of thermoelectric conduction legs 208, which will be describedin further detail below.

In some embodiments, the intermediate thermoelectric conductionstructures 210-1A and 210-1B may be formed as a pair, and each of thepair is disposed at a respective end of the thermoelectric conductionleg 208-1; the intermediate thermoelectric conduction structures 210-2Aand 210-2B may be formed as a pair, and each of the pair is disposed ata respective end of the thermoelectric conduction leg 208-2; theintermediate thermoelectric conduction structures 210-3A and 210-3B maybe formed as a pair, and each of the pair is disposed at a respectiveend of the thermoelectric conduction leg 208-3; the intermediatethermoelectric conduction structures 210-4A and 210-4B may be formed asa pair, and each of the pair is disposed at a respective end of thethermoelectric conduction leg 208-4; the intermediate thermoelectricconduction structures 210-5A and 210-5B may be formed as a pair, andeach of the pair is disposed at a respective end of the thermoelectricconduction leg 208-5; the intermediate thermoelectric conductionstructures 210-6A and 210-6B may be formed as a pair, and each of thepair is disposed at a respective end of the thermoelectric conductionleg 208-6; the intermediate thermoelectric conduction structures 210-7Aand 210-7B may be formed as a pair, and each of the pair is disposed ata respective end of the thermoelectric conduction leg 208-7.

In some embodiments, each of the plurality of intermediatethermoelectric conduction structures 210 is formed of a polysiliconmaterial. Moreover, in some embodiments, each of the plurality ofintermediate thermoelectric conduction structures 210 is formed of ann-type polysilicon material, for example, a polysilicon material dopedwith phosphorus, arsenic, antimony, or the like.

Similarly, as mentioned above, each of the operations of the method 100(FIG. 1) is BiCMOS compatible, in accordance with some embodiments. Assuch, in some embodiments, each of the plurality of thermoelectricconduction structures 210, formed in the operation 108 of FIG. 1, mayinclude an emitter feature of a respective BJT. In some embodiments,such an “emitter” thermoelectric conduction structure 210 may be formedusing a suitable base-forming process BiCMOS technologies such as, forexample, ALD, CVD, PVD, plating, or a combination thereof.

Corresponding to operation 110 of FIG. 1, FIG. 2E is a perspective viewof the thermocouple device 200 including a plurality of contactstructures 212, which are at one of the various stages of fabrication,according to some embodiments. In some embodiments, the contactstructure 212 may be formed of a conductive material such as, forexample, copper, silver, gold, tungsten, or a combination thereof.

In some embodiments, the plurality of contact structures 212 may includetwo portions 212A and 212B. More specifically, the first portion 212A(e.g., 212A-1, 212A-2, 212A-3, 212A-4, 212A-5, 212A-6, and 212A-7) ofthe contact structures 212 are each coupled between respective ones ofthe first and second pluralities of thermoelectric conduction legs (204and 208) that are disposed end-to-end along the respective row (the Xdirection); and part of the second portion 212B (e.g., 212B-1, 212B-2,212B-3, 212B-4, 212B-5, and 212B-6) of the contact structures 212 areeach coupled between respective ones of the first and second pluralitiesof thermoelectric conduction legs (204 and 208) that are disposedside-by-side along a respective column (the Y direction), which will bediscussed in further detail below. It is noted that, in someembodiments, contact structure 212B-7 of the second portion 212B isdisposed on the intermediate thermoelectric conduction structure 210-6B,which is at an end of the thermoelectric conduction leg 208-6; andcontact structure 212B-8 of the second portion 212B is disposed at anend of the thermoelectric conduction leg 204-7 (i.e., the contactstructures 212B-7 and 212B-8 is coupled only to a respectivethermoelectric conduction leg).

Referring first to the first portion 212A of the contact structures inFIG. 2E, in some embodiments, the contact structure 212A-1 is formed tocouple the end-to-end thermoelectric conduction legs 208-6 and 204-1through the intermediate thermoelectric conduction structure 210-6A anddirectly, respectively; the contact structure 212A-2 is formed to couplethe end-to-end thermoelectric conduction legs 208-1 and 204-2 throughthe intermediate thermoelectric conduction structure 210-1B anddirectly, respectively; the contact structure 212A-3 is formed to couplethe end-to-end thermoelectric conduction legs 208-2 and 204-3 throughthe intermediate thermoelectric conduction structure 210-2A anddirectly, respectively; the contact structure 212A-4 is formed to couplethe end-to-end thermoelectric conduction legs 208-3 and 204-4 throughthe intermediate thermoelectric conduction structure 210-3B anddirectly, respectively; the contact structure 212A-5 is formed to couplethe end-to-end thermoelectric conduction legs 208-4 and 204-5 throughthe intermediate thermoelectric conduction structure 210-4A anddirectly, respectively; the contact structure 212A-6 is formed to couplethe end-to-end thermoelectric conduction legs 208-5 and 204-6 throughthe intermediate thermoelectric conduction structure 210-5B anddirectly, respectively; the contact structure 212A-7 is formed to couplethe end-to-end thermoelectric conduction legs 208-7 and 204-7 throughthe intermediate thermoelectric conduction structure 210-7A anddirectly, respectively.

Referring then to the second portion 212B of the contact structures inFIG. 2E, in some embodiments, the contact structure 212B-1 is formed tocouple the side-by-side thermoelectric conduction legs 204-1 and 208-1directly and through the intermediate thermoelectric conductionstructure 210-1A, respectively; the contact structure 212B-2 is formedto couple the side-by-side thermoelectric conduction legs 204-3 and208-3 directly and through the intermediate thermoelectric conductionstructure 210-3A, respectively; the contact structure 212B-3 is formedto couple the side-by-side thermoelectric conduction legs 204-5 and208-5 directly and through the intermediate thermoelectric conductionstructure 210-5A, respectively; the contact structure 212B-4 is formedto couple the side-by-side thermoelectric conduction legs 204-2 and208-2 directly and through the intermediate thermoelectric conductionstructure 210-2B, respectively; the contact structure 212B-5 is formedto couple the side-by-side thermoelectric conduction legs 204-4 and208-4 directly and through the intermediate thermoelectric conductionstructure 210-4B, respectively; the contact structure 212B-6 is formedto couple the side-by-side thermoelectric conduction legs 204-6 and208-7 directly and through the intermediate thermoelectric conductionstructure 210-7B, respectively.

As such, plural sub thermocouple devices 220-1, 220-2, 220-3, 220-4,220-5, 220-6 and 220-7 can be formed on the substrate 202, which isshown in FIG. 2F. It is noted that FIG. 2F is reproduced from FIG. 2E,and for purposes of clarity of illustration, some numeric references inFIG. 2E are not repeated in FIG. 2F. Taking the sub thermocouple device220-1 as a representative example, in some embodiments, each of the subthermocouple devices is constituted of the respective ones of the firstand second pluralities of thermoelectric conduction legs (e.g., 204-1and 208-6) that are coupled to each other end-to-end by a respective oneof the first portion (e.g., 212A-1) of the contact structures 212 and arespective one of the intermediate thermoelectric conduction structure(e.g., 201-6A).

Further, the sub thermocouple devices 220-1 to 220-7 formed along therespective rows can be coupled to each other by a respective one of thesecond portion 212B of the contact structures 212, in accordance withsome embodiments. As such, the sub thermocouple devices 220-1 to 220-7may be “electrically” coupled in series when a current/voltage signal isgenerated from each sub thermocouple device, which will be discussed infurther detail below.

For example, the sub thermocouple device 220-1 is coupled to the subthermocouple device 220-2 by the contact structure 212B-1; the subthermocouple device 220-2 is further coupled to the sub thermocoupledevice 220-3 by the contact structure 212B-4; the sub thermocoupledevice 220-2 is further coupled to the sub thermocouple device 220-3 bythe contact structure 212B-4; the sub thermocouple device 220-3 isfurther coupled to the sub thermocouple device 220-4 by the contactstructure 212B-2; the sub thermocouple device 220-4 is further coupledto the sub thermocouple device 220-5 by the contact structure 212B-5;the sub thermocouple device 220-5 is further coupled to the subthermocouple device 220-6 by the contact structure 212B-3; and the subthermocouple device 220-6 is further coupled to the sub thermocoupledevice 220-7 by the contact structure 212B-6. Thereafter, according tosome embodiments, the sub thermocouple devices 220-1 to 220-7 may be“electrically” coupled in series.

Corresponding to operation 112 of FIG. 1, FIG. 2G is a perspective viewof the thermocouple device 200 including a dielectric layer 228overlaying the sub thermocouple devices 220-1 to 220-7, which is formedat one of the various stages of fabrication, according to someembodiments. The dielectric layer 228 may include one or more dielectricmaterials such as silicon nitride (SiN), silicon oxide (SiO), siliconcarbide (SiC), silicon oxycarbide (SiOC), silicon oxycarbon nitride(SiOCN), and/or a combination thereof. The dielectric layer 228 mayinclude a single layer or a multi-layer structure. The dielectric layer228 may be formed by chemical oxidation, thermal oxidation, ALD, CVD,and/or other suitable methods.

Corresponding to operation 114 of FIG. 1, FIG. 2H is a perspective viewof the thermocouple device 200 including a patterned mask layer 230overlaying the dielectric layer 228, which is formed at one of thevarious stages of fabrication, according to some embodiments, and FIG.2I is a corresponding top view of FIG. 2H. In some embodiments, thepatterned mask layer 230 may be formed of a photoresist material, a hardmask material (e.g., SiN), or the like.

In some embodiments, the patterned mask layer 230 includes one or moreopenings 231-1, 231-2, 231-3, 231-4, 231-5, 231-6, 231-7, 231-8, 231-9,231-10, 231-11, and 231-12. Each of the openings (231-1 to 231-12) isaligned to a location on the substrate 202 located between respectivethermoelectric conduction legs that belong to two adjacent subthermocouple devices (e.g., 220-1 to 220-7), respectively, which isshown in the illustrated embodiment of FIG. 2I.

More specifically, the opening 231-1 is aligned to the location disposedbetween the thermoelectric conduction legs 204-1 and 208-1 that belongto the adjacent sub thermocouple devices 220-1 and 220-2, respectively;the opening 231-2 is aligned to the location disposed between thethermoelectric conduction legs 204-3 and 208-1 that belong to theadjacent sub thermocouple devices 220-3 and 220-2, respectively; theopening 231-3 is aligned to the location disposed between thethermoelectric conduction legs 208-3 and 204-3 that belong to theadjacent sub thermocouple devices 220-4 and 220-3, respectively; theopening 231-4 is aligned to the location disposed between thethermoelectric conduction legs 204-5 and 208-3 that belong to theadjacent sub thermocouple devices 220-5 and 220-4, respectively; theopening 231-5 is aligned to the location disposed between thethermoelectric conduction legs 208-5 and 204-5 that belong to theadjacent sub thermocouple devices 220-6 and 220-5, respectively; theopening 231-6 is aligned to the location disposed between thethermoelectric conduction legs 204-7 and 208-5 that belong to theadjacent sub thermocouple devices 220-7 and 220-6, respectively; theopening 231-7 is aligned to the location disposed between thethermoelectric conduction legs 204-2 and 208-6 that belong to theadjacent sub thermocouple devices 220-2 and 220-1, respectively; theopening 231-8 is aligned to the location disposed between thethermoelectric conduction legs 204-2 and 208-2 that belong to theadjacent sub thermocouple devices 220-2 and 220-3, respectively; theopening 231-9 is aligned to the location disposed between thethermoelectric conduction legs 204-4 and 208-2 that belong to theadjacent sub thermocouple devices 220-4 and 220-3, respectively; theopening 231-10 is aligned to the location disposed between thethermoelectric conduction legs 208-4 and 204-4 that belong to theadjacent sub thermocouple devices 220-5 and 220-4, respectively; theopening 231-11 is aligned to the location disposed between thethermoelectric conduction legs 204-6 and 208-4 that belong to theadjacent sub thermocouple devices 220-6 and 220-5, respectively; and theopening 231-12 is aligned to the location disposed between thethermoelectric conduction legs 208-7 and 204-6 that belong to theadjacent sub thermocouple devices 220-7 and 220-6, respectively.

Corresponding to operation 116 of FIG. 1, FIG. 2J is a perspective viewof the thermocouple device 200 including one or more trenches 240between adjacent sub thermocouple devices (e.g., 220-1 to 220-7), whichare formed at one of the various stages of fabrication, according tosome embodiments, FIG. 2K is a corresponding top view of thethermocouple device 200, and FIG. 2L is a corresponding cross-sectionalview, taken along line A-A, of the thermocouple device 200. In someembodiments, the trenches 240 are formed by performing at least one dryor wet etching process 250 on the dielectric layer 228 and the substrate202 while using the patterned mask layer 230 as a mask. In someembodiments, the etching process 250 may include two sub processes thatare performed to etch through the dielectric layer 228 and recess a topportion of the substrate 202, respectively, which will be illustratedand discussed in FIGS. 4A and 4B. As will be discussed below, thelocations of the trenches 240 on a top surface of the substrate 202 maycorrespond to the openings (231-1 to 231-12 in FIG. 2H), which arecollectively referred to as opening 231.

In some embodiments, the trenches 240 include: trenches 240-1, 240-2,240-3, 240-4, 240-5, 240-6, 240-7, 240-8, 240-9, 240-10, 240-11, and240-12 as shown in FIG. 2K, wherein each of the trenches is locatedbetween respective thermoelectric conduction legs (e.g., 204-1 to 204-7,and 208-1 to 208-7) of the two closest sub thermocouple devices (e.g.,220-1 to 220-7), which will be discussed in further detail below withrespect to FIG. 2K. More specifically, each of the trenches (240-1 to240-12) is substantially adjacent to respective side edges of thethermoelectric conduction legs (e.g., 204-1 to 204-7, and 208-1 to208-7) of the two closest sub thermocouple devices (e.g., 220-1 to220-7).

In the illustrated embodiment of FIG. 2K, the trench 240-1 is locatedbetween the thermoelectric conduction legs 208-6 and 204-2 that belongto the sub thermocouple devices 220-1 and 220-2, respectively; thetrench 240-2 is located between the thermoelectric conduction legs 204-2and 208-2 that belong to the sub thermocouple devices 220-2 and 220-3,respectively; the trench 240-3 is located between the thermoelectricconduction legs 208-2 and 204-4 that belong to the sub thermocoupledevices 220-3 and 220-4, respectively; the trench 240-4 is locatedbetween the thermoelectric conduction legs 204-4 and 208-4 that belongto the sub thermocouple devices 220-4 and 220-5, respectively; thetrench 240-5 is located between the thermoelectric conduction legs 208-4and 204-6 that belong to the sub thermocouple devices 220-5 and 220-6,respectively; the trench 240-6 is located between the thermoelectricconduction legs 204-6 and 208-7 that belong to the sub thermocoupledevices 220-6 and 220-7, respectively; the trench 240-7 is locatedbetween the thermoelectric conduction legs 204-1 and 208-1 that belongto the sub thermocouple devices 220-1 and 220-2, respectively; thetrench 240-8 is located between the thermoelectric conduction legs 208-1and 204-3 that belong to the sub thermocouple devices 220-2 and 220-3,respectively; the trench 240-9 is located between the thermoelectricconduction legs 204-3 and 208-3 that belong to the sub thermocoupledevices 220-3 and 220-4, respectively; the trench 240-10 is locatedbetween the thermoelectric conduction legs 208-3 and 204-5 that belongto the sub thermocouple devices 220-4 and 220-5, respectively; thetrench 240-11 is located between the thermoelectric conduction legs204-5 and 208-5 that belong to the sub thermocouple devices 220-5 and220-6, respectively; the trench 240-12 is located between thethermoelectric conduction legs 208-5 and 204-7 that belong to the subthermocouple devices 220-6 and 220-7, respectively.

Referring to the illustrated embodiment of FIG. 2L, respective recessedprofiles of the trenches 240-1 to 240-6 are shown (after the removal ofthe patterned mask layer 230 and the dielectric layer 228). In someembodiments, each of the trenches 240 may have a depth about 10micrometer (μm). In some other embodiments, the second sub process ofthe etching process 250 may “over recess” the substrate 202. As such,each of the trenches 240 may have a respective recessed profile (e.g.,241-1) that outwardly extends beyond vertical projections (e.g., lines Band B′) of respective thermoelectric conduction legs (e.g., 208-6 and204-2).

FIG. 3 illustrates a cross-sectional view of the sub thermocouple device220-1, in accordance with some embodiments. It is noted that operationsof the sub thermocouple device (220-1 to 220-7) of the thermocoupledevice 200 are substantially similar to each other. Thus, the subthermocouple device 220-1 is reproduced in FIG. 3 as a representativeexample to illustrate the operation of each of the sub thermocoupledevice (220-1 to 220-7).

In some embodiments, the thermocouple device 200 may be placed in anenvironment having a temperature gradient to generate electric power, asmentioned above. More specifically, the thermocouple device 200 may becoupled to a first temperature T₁ at a first interface and to a secondtemperature T₂ at a second interface, wherein T₁ is substantially higherthan T₂. Using the sub thermocouple device 220-1 as an example, the subthermocouple device 220-1 is coupled to the temperature T₁ at thecontact structure 212A-1's top surface 212A-1T, and to the temperatureT₂ at the substrate 202's bottom surface 202B.

Due to a temperature gradient between T₁ and T₂, a first thermal flowmay follow symbolic directions 305 traveling from the contact structure212A-1 and through the intermediate thermoelectric conduction structure210-6A, then 307 traveling along the thermoelectric conduction leg208-6, and 309 traveling through the substrate 202 and to the bottomsurface 202B; and a second thermal flow may follow symbolic directions355 traveling from the contact structure 212A-1, then 357 travelingalong the thermoelectric conduction leg 204-1, and 359 traveling throughthe substrate 202 and to the bottom surface 202B.

Moreover, a plurality of hot holes (e.g., 302) may be induced in thep-type doped thermoelectric conduction leg 208-6, and a plurality of hotelectrons (e.g., 352) may be induced in the n-type doped thermoelectricconduction leg 204-1. As such, electric power (e.g., a voltage/currentsignal) can be collected from the contact structures 212B-7 and 212B-1.As mentioned above, the contact structure 212B-1 is configured toelectrically couple the sub thermocouple device 220-1 to the subthermocouple device 220-2 (FIG. 2F), and since the sub thermocoupledevice 220-2 may generate a respective voltage/current signal, thevoltage/current signals, respectively generated by the sub thermocoupledevices 220-1 and 220-2, may be electrically coupled in series (e.g.,superimposed). Analogously, each of the rest sub thermocouple devices(202-3 to 202-7) is coupled to a respective sub thermocouple device insimilar fashion as the sub thermocouple devices 220-1 and 220-2.Thereafter, in some embodiments, the thermocouple device 200 canelectrically superimpose plural voltage/current signals that aregenerated by the sub thermocouple devices (220-1 to 220-7).

The trenches 240 (e.g., 240-1 and 240-7 shown in FIG. 3), formed betweenadjacent sub thermocouple devices, can further provide thermalinsulation for each of the sub thermocouple devices (220-1 to 220-7), inaccordance with some embodiments. More specifically, by forming thetrenches 240, each of the sub thermocouple devices (220-1 to 220-7) maybe effectively provided with a substantially larger temperature gradient(e.g., larger than T₁−T₂), which advantageously increase a respectivelevel of the generated voltage/current signal.

Further, in some embodiments, after the formation of the trenches 240, aportion of the substrate 202 that is located between respectivethermoelectric conduction legs (204 and 208) of each sub thermocoupledevice (220-1 to 220-7) may remain intact. Such a portion of thesubstrate 202, e.g., 270 in FIG. 3, may serve as a support structure forthe sub thermocouple devices (220-1 to 220-7). In some embodiments, whenthe trench 240 has a depth of about 10 μm and the first portion of thecontact structure 212A has a length 212A′ of about 12 μm to about 15 μm,the support structure 270 may have a width 270′ of about 2 μm to 4 μm.

As mentioned above, in some embodiments, the etching process 250 mayinclude two sub processes, e.g., 250-1 and 250-2, performed to etch thedielectric layer 228 and recess a top portion of the substrate 202,respectively. FIGS. 4A and 4B respectively illustrate cross-sectionalview of the thermocouple device 200, taken along line A-A (FIG. 2J),when the first sub process 250-1 and second sub-process 250-2 areperformed. Referring to FIG. 4A, in some embodiments, the first subprocess 250-1 is first performed that uses an anisotropic etchingprocess (e.g., an inductively coupled plasma (ICP) process) to etch thedielectric layer 228 through respective openings (e.g., 231-7 to 231-12as shown in FIG. 4A) of the patterned mask layer 230. The first subprocess 250-1 may be configured to remove (e.g., etch) plural portionsof the dielectric layer 228 that are disposed between respectivethermoelectric conduction legs of the plural sub thermocouple devices.

For example, a portion of the dielectric layer 228 that is disposedbetween the thermoelectric conduction legs (208-6, 210-6B, and 212B-7)of the sub thermocouple device 220-1 and the thermoelectric conductionleg (204-2) of the sub thermocouple device 220-2 is etched by the firstsub process 250-1 through the opening 231-7. Similarly, a portion of thedielectric layer 228 that is disposed between the thermoelectricconduction leg (204-2) of the sub thermocouple device 220-2 and thethermoelectric conduction legs (208-2 and 210-2B) of the subthermocouple device 220-3 is etched by the first sub process 250-1through the opening 231-8; a portion of the dielectric layer 228 that isdisposed between the thermoelectric conduction legs (208-2 and 210-2B)of the sub thermocouple device 220-3 and the thermoelectric conductionleg (204-4) of the sub thermocouple device 220-4 is etched by the firstsub process 250-1 through the opening 231-9; and so on. It is noted thata portion of the dielectric layer that are not exposed by the openingsof the patterned mask layer 230 (e.g., portions of the dielectric layer228 shown in FIG. 4A) may remain intact through the first sub process250-1 due to the anisotropic characteristic of the first sub process250-1.

Referring to FIG. 4B, in some embodiments, the second sub process 250-2may be subsequently performed that uses an isotropic etching process(e.g., a reactive ion etching (RIE) process) to recess the top surfaceof the substrate 202. Due to the isotropic characteristic of the secondsub process 250-2, remaining portions of the dielectric layer 228 can beremoved, and further, the trenches (e.g., 240-1 to 240-6) betweenrespective sub thermocouple devices (e.g., 220-1 to 220-7) can beformed. In some embodiments, each the trenches 240 may have an aspectratio (width/depth) of about 0.2 to about 0.5. As mentioned above, thepresence of the trenches 240 between respective sub thermocouple devices(220-1 to 220-7) can advantageously increase the respective level of thevoltage/current signal generated by each of the sub thermocouple devices(220-1 to 220-7). After the at least two sub processes (250-1 and 250-2)of the etching process 250, the patterned mask layer 230 is removed.

In an embodiment, a semiconductor device is disclosed. The semiconductordevice includes a substrate; a first thermoelectric conduction leg,disposed on the substrate, and doped with a first type of dopant; asecond thermoelectric conduction leg, disposed on the substrate, anddoped with a second type of dopant, wherein the first and secondthermoelectric conduction legs are spatially spaced from each other butdisposed along a common row on the substrate; and a first intermediatethermoelectric conduction structure, disposed on a first end of thesecond thermoelectric conduction leg, and doped with the first type ofdopant.

Yet in another embodiment, a semiconductor device includes a substrate;a first thermocouple device, disposed along a first row on thesubstrate, comprising a first thermoelectric conduction leg, a secondthermoelectric conduction leg, and a first contact structure couplingthe first and second thermoelectric conduction legs via a firstintermediate thermoelectric conduction structure; and a secondthermocouple device, disposed along a second row on the substrate,comprising a third thermoelectric conduction leg, a fourththermoelectric conduction leg, and a second contact structure couplingthe third and fourth thermoelectric conduction legs via a secondintermediate thermoelectric conduction structure.

Yet in another embodiment, a method includes forming a firstthermoelectric conduction leg on a substrate; forming a secondthermoelectric conduction leg on a substrate, wherein the secondthermoelectric conduction leg is aligned with the first thermoelectricconduction leg along a same row; forming at least one intermediatethermoelectric conduction structure on an end of the secondthermoelectric conduction leg; forming a contact structure coupling thefirst and second thermoelectric conduction legs via the at least oneintermediate thermoelectric conduction structure; and recessing thesubstrate to form a trench substantially adjacent to a respective sideedge of either the first thermoelectric conduction leg or the secondthermoelectric conduction leg.

The foregoing outlines features of several embodiments so that thoseordinary skilled in the art may better understand the aspects of thepresent disclosure. Those skilled in the art should appreciate that theymay readily use the present disclosure as a basis for designing ormodifying other processes and structures for carrying out the samepurposes and/or achieving the same advantages of the embodimentsintroduced herein. Those skilled in the art should also realize thatsuch equivalent constructions do not depart from the spirit and scope ofthe present disclosure, and that they may make various changes,substitutions, and alterations herein without departing from the spiritand scope of the present disclosure.

What is claimed is:
 1. A method, comprising: forming a firstthermoelectric conduction leg on a substrate; forming a secondthermoelectric conduction leg on the substrate to be aligned with thefirst thermoelectric conduction leg along a same row; forming at leastone intermediate thermoelectric conduction structure on an end of thesecond thermoelectric conduction leg; forming a contact structure tocouple the first and second thermoelectric conduction legs via the atleast one intermediate thermoelectric conduction structure; andrecessing the substrate to form at least one trench substantiallyadjacent to a respective side edge of either the first thermoelectricconduction leg or the second thermoelectric conduction leg, wherein afirst end of the second thermoelectric conduction leg is substantiallycloser to the first thermoelectric conduction leg than a second end ofthe second thermoelectric conduction leg.
 2. The method of claim 1,wherein first thermoelectric conduction leg comprises an n-type dopedpolysilicon material, the second thermoelectric conduction leg comprisesa p-type doped silicon-germanium material, and the least oneintermediate thermoelectric conduction structure comprises the n-typedoped polysilicon material.
 3. The method of claim 1, wherein formingthe contact structure comprises: forming a first contact structuredisposed on the at least one intermediate thermoelectric conductionstructure and a first end of the first thermoelectric conduction leg. 4.The method of claim 3, wherein forming the contact structure furthercomprises: forming a second contact structure disposed on a second endof the first thermoelectric conduction leg, wherein the second end isopposite to the first end.
 5. The method of claim 1, recessing thesubstrate to form at least one trench comprises: forming a first trenchdisposed on a top surface of the substrate; and forming a second trenchdisposed on the top surface of the substrate.
 6. The method of claim 1,wherein the first thermoelectric conduction leg comprises a polysiliconmaterial, the second thermoelectric conduction leg comprises asilicon-germanium material, and the at least one intermediatethermoelectric conduction structure comprises the polysilicon material.7. A method, comprising: providing a substrate; forming a firstthermoelectric conduction leg on the substrate, where the firstthermoelectric conduction leg is doped with a first type of dopant;forming a second thermoelectric conduction leg on the substrate, whereinthe second thermoelectric conduction leg is doped with a second type ofdopant, wherein the first and second thermoelectric conduction legs arespatially spaced from each other but disposed along a common row on thesubstrate; forming a first intermediate thermoelectric conductionstructure on a first end of the second thermoelectric conduction leg,wherein the first intermediate thermoelectric conduction structure isdoped with the first type of dopant; and forming a second intermediatethermoelectric conduction structure on a second end of the secondthermoelectric conduction leg, wherein the second intermediatethermoelectric conduction structure is doped with the first type ofdopant, wherein the second end is opposite to the first end.
 8. Themethod of claim 7, wherein the first type of dopant comprises an n-typeof dopant, and the second type of dopant comprises a p-type of dopant.9. The method of claim 7, wherein the first thermoelectric conductionleg comprises a polysilicon material, the second thermoelectricconduction leg comprises a silicon-germanium material, and the firstintermediate thermoelectric conduction structure comprises thepolysilicon material.
 10. The method of claim 7, wherein the first endof the second thermoelectric conduction leg is substantially closer tothe first thermoelectric conduction leg than the second end of thesecond thermoelectric conduction leg.
 11. The method of claim 7, furthercomprising: forming a first contact structure disposed on the firstintermediate thermoelectric conduction structure and a first end of thefirst thermoelectric conduction leg.
 12. The method of claim 11, furthercomprising: forming a second contact structure disposed on a second endof the first thermoelectric conduction leg, wherein the second end isopposite to the first end.
 13. The method of claim 7, furthercomprising: forming a first trench disposed on a top surface of thesubstrate; forming a second trench disposed on the top surface of thesubstrate; and forming a support structure, wherein the first and secondtrenches are substantially adjacent to respective side edges of thefirst and second thermoelectric conduction legs, and the supportstructure is disposed between the first and second thermoelectricconduction legs.
 14. A method, comprising: providing a substrate;forming a first thermocouple device along a first row on the substrate,the first thermocouple device comprising a first thermoelectricconduction leg, a second thermoelectric conduction leg, and a firstcontact structure coupling the first and second thermoelectricconduction legs via a first intermediate thermoelectric conductionstructure; forming a second thermocouple device along a second row onthe substrate, the second thermocouple device comprising a thirdthermoelectric conduction leg, a fourth thermoelectric conduction leg,and a second contact structure coupling the third and fourththermoelectric conduction legs via a second intermediate thermoelectricconduction structure; and forming a third contact structure coupling thefirst thermoelectric conduction leg of the first thermocouple device andthe third thermoelectric conduction leg of the second thermocoupledevice via a third intermediate thermoelectric conduction structure,wherein the third intermediate thermoelectric conduction structure isdisposed on a first end of the third thermoelectric conduction leg ofthe second thermocouple device, and the second intermediatethermoelectric conduction structure is disposed on a second end of thethird thermoelectric conduction leg of the second thermocouple device,the first and second ends being opposite to each other.
 15. The methodof claim 14, wherein the first and fourth thermoelectric conductionlegs, and the first and second intermediate thermoelectric conductionstructures are doped with a first type of dopant, and the second andthird thermoelectric conduction legs are doped with a second type ofdopant.
 16. The method of claim 15, wherein the first type of dopantcomprises an n-type of dopant, and the second type of dopant comprises ap-type of dopant.
 17. The method of claim 14, wherein the first andfourth thermoelectric conduction legs, and the first and secondintermediate thermoelectric conduction structures each comprises apolysilicon material.
 18. The method of claim 14, wherein the second andthird thermoelectric conduction legs each comprises a silicon-germaniummaterial.
 19. The method of claim 14, wherein the first thermoelectricconduction leg comprises a polysilicon material, the secondthermoelectric conduction leg comprises a silicon-germanium material,and the first intermediate thermoelectric conduction structure comprisesthe polysilicon material.
 20. The method of claim 14, wherein the firstend of the second thermoelectric conduction leg is substantially closerto the first thermoelectric conduction leg than the second end of thesecond thermoelectric conduction leg.